In flat displays like plasma display panels (PDPS) and liquid crystal displays (LCDs), the display panel is driven by a clock signal generated in accordance with a fixed-frequency, which may result in noise problem if the frequency is audible. One solution according to the prior art may simply shift the frequency of the clock signal beyond or below the audible range.
Another solution is to modulate the frequency of the clock signal to spread its spectrum, as shown in FIG. 1. To reduce acoustic noise, the spectrum of the clock signal is spread to decrease the intensity of noise peak, as illustrated by the spectrum 104, compared with the original spectrum 102. For example, the prior art achieves it by continuously varying the frequency of the clock signal, as shown in FIG. 2, so as to spread out noise that the display panel emits.
However, current approaches to reduce noise involve problems in terms of stable operation of the display and the cost of the display, higher power consumption, and drastic measures for solution are needed. Therefore, it is desired to have a novel flat display and a method for modulating a clock signal for driving the display.